What's too loud: Federal OSHA standards say the ear can tolerate eight hours a day of 90-decibel sound (the sound of a well-tuned power mower), four hours at 95 decibels, two hours at 100 decibels, and so on. Many audiologists say those times should be cut in half.
Ear pain begins at 125 decibels (ambulance siren), permanent damage with short exposure at 140 decibels (gunshot), and death of hearing tissue at 180 decibels (rocket launch).